Question

我正试图在日食上放置多个圆圈，并能够围绕日食移动那个圆圈。从查看PyGames的例子我已经看到你可以围绕日食旋转一条线但是无法弄清楚如何处理一个圆圈。

这是我在尝试时收到的错误消息：

Traceback (most recent call last):
File "C:/Python32/Attempts/simple_graphics_demo.py", line 66, in <module>
pygame.draw.circle(screen, BLUE, [x, y], 15, 3)
TypeError: integer argument expected, got float

import pygame
import math

# Initialize the game engine
pygame.init()

# Colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)
BLUE = (0, 0, 255)

PI = 3.141592653

# Set the height and width of the screen
size = [400, 400]
screen = pygame.display.set_mode(size)

my_clock = pygame.time.Clock()

# Loop until the user clicks the close button.
done = False

angle = 0

while not done:
for event in pygame.event.get():
    if event.type == pygame.QUIT:
        done = True

# Set the screen background
screen.fill(WHITE)

# Dimensions of radar sweep
# Start with the top left at 20,20
# Width/height of 250
box_dimensions = [20, 20, 250, 250]

# Draw the outline of a circle to 'sweep' the line around
pygame.draw.ellipse(screen, GREEN, box_dimensions, 2)

# Draw a black box around the circle
pygame.draw.rect(screen, BLACK, box_dimensions, 2)

# Calculate the x,y for the end point of our 'sweep' based on
# the current angle
x = 125 * math.sin(angle) + 145
y = 125 * math.cos(angle) + 145

# Draw the line from the center at 145, 145 to the calculated
# end spot
pygame.draw.line(screen, GREEN, [145, 145], [x, y], 2)

# Attempt to draw a circle on the radar
pygame.draw.circle(screen, BLUE, [x, y], 15, 3)

# Increase the angle by 0.03 radians
angle = angle + .03

# If we have done a full sweep, reset the angle to 0
if angle > 2 * PI:
    angle = angle - 2 * PI

# Flip the display, wait out the clock tick
pygame.display.flip()
my_clock.tick(60)

# on exit.
pygame.quit()

Answer 1

math.sin和math.cos函数返回浮点数，而pygame.draw.circle的pos关键字参数需要整数位置，因此您需要实际投射坐标。您可以选择以下几种方法：

[int(x), int(y)]
[math.floor(x), math.floor(y)]
[math.ceil(x), math.ceil(y)]

每个都有不同的行为，所以你可能想知道哪个最适合你的程序。（具体来说：int和floor对负数的工作方式不同 - int向0和floor向下舍入，如预期的那样）

Answer 2

你的主要问题不是答案 - 因为你已经得到答案。

要放置更多圆圈，请使用带有角度的列表和for循环来从列表中获取角度（逐个）并绘制圆圈。

import pygame
import math

# === CONSTANTS ===

BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED   = (255, 0, 0)
BLUE  = (0, 0, 255)

SIZE = (400, 400)

TWO_PI = 2 * math.pi # you don't have to calculate it in loop

# === MAIN ===

# --- init ---

pygame.init()

screen = pygame.display.set_mode(SIZE)

# --- objects ---

angles = [0, 1, math.pi] # angles for many circles

box_dimensions = [20, 20, 250, 250] # create only once

# --- mainloop ---

clock = pygame.time.Clock()
done = False

while not done:

    # --- events ---

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                done = True

    # --- draws (without updates) ---

    screen.fill(WHITE)

    pygame.draw.ellipse(screen, GREEN, box_dimensions, 2)

    pygame.draw.rect(screen, BLACK, box_dimensions, 2)

    # draw many circles 
    for a in angles: 

        x = int(125 * math.sin(a)) + 145
        y = int(125 * math.cos(a)) + 145

        pygame.draw.line(screen, GREEN, [145, 145], [x, y], 2)
        pygame.draw.circle(screen, BLUE, [x, y], 15, 3)

    pygame.display.flip()
    clock.tick(60)

    # --- updates (without draws) ---

    # new values for many angles
    for i, a in enumerate(angles):
        a += .03

        if a > TWO_PI:
            a -= TWO_PI

        angles[i] = a

# --- the end ---
pygame.quit()

PyGame / Python：将圆圈放在椭圆上

2 个答案: